1. Field of the Invention
The invention relates to a light-emitting device.
2. Related Art
A conventional light-emitting device is known that uses a thermosetting resin such as epoxy resin or silicone resin as a material for sealing a light-emitting element (see, e.g., JP-A-2010-199229).
In general, a thermosetting resin such as epoxy resin or silicone resin is poured into a recessed portion of a resin case having a light-emitting element placed therein and is then cured by heating. However, such a thermosetting resin has a disadvantage in that it is cured before being poured into the resin case during a manufacturing process since viscosity increases due to reaction which proceeds gradually even at room temperature and this produces a portion which has to be discarded. This increases a manufacturing cost of the sealing material, as a result.
On the other hand, a radical polymerizable resin, which is stable at room temperature and is instantaneously and progressively polymerized at a high temperature, is known. However, it is known that cure inhibition caused by oxygen is likely to occur on a surface of the radical polymerizable resin in contact with the air, which causes insufficient curing and likely causes tackiness (see, e.g., JP-A-2007-184404). Accordingly, in case that the radical polymerizable resin is used as a sealing material, there is a problem that it is necessary to eliminate oxygen by flowing an inert gas such as nitrogen gas into a hardening furnace and this increases the manufacturing cost.